@Reid_Alexander I suspect that the Admin may have switched off the ability for users to add their own backgrounds (NoFilters). This is managed via PowerShell and cannot be seen in the Teams Admin portal.
See Microsoft Docs info
Meeting policy settings - Video filters mode
This is a per-user policy. This setting controls whether users can customize their video background in a meeting.
Currently, you can only use PowerShell to set this policy. You can edit an existing Teams meeting policy by using the Set-CsTeamsMeetingPolicy cmdlet. Or, create a new Teams meeting policy by using the New-CsTeamsMeetingPolicy cmdlet, and then assign the policy to users.
To specify whether users can customize their video background in a meeting, set the VideoFiltersMode parameter as follows:
